Field_Temperature Phase Diagram of Intergrain Ordering in Superconducting Ceramic YBCO

29th International Symposium on Superconductivity

Deguchi, H.^1 ; Warabino, R.^1 ; Ka, S.^1 ; Mito, M.^1 ; Hagiwara, M.^2 ; Koyama, K.^3

Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu

804-8550, Japan^1

Faculty of Engineering and Design, Kyoto Institute of Technology, Kyoto

606-8585, Japan^2

Faculty of Science and Technology, Tokushima University, Tokushima

770-8502, Japan^3

关键词: Coupled networks;    Field dependence;    Field temperature;    Nonlinear susceptibilities;    Submicron grains;    Superconducting ceramics;    Superconducting transitions;    Superconductive transition;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/871/1/012011/pdf
DOI  :  10.1088/1742-6596/871/1/012011

来源: IOP

【 摘 要 】

The ceramic YBa2Cu4O8superconductor composed of submicron grains is considered a random Josephson-coupled network containing the so-called π junctions and shows successive phase transitions. With decreasing temperature, first the intragrain superconductive transition occurs inside each grain at Tc1and then the chiral-glass transition occurs among the grains at Tc2(c1). The third transition at Tc3(c2) is the intergrain superconducting transition. We measured the nonlinear susceptibility and resistivity of the ceramic YBa2Cu4O8superconductor to determine the field dependences of the transition temperatures Tc2and Tc3. The phase diagram of the intergrain ordering is discussed in light of the result predicted by Kawamura.